Sigma hf x80

stormtracker78

Member
Premium Subscriber
Joined
Feb 6, 2011
Messages
114
Location
Cameron County, Tx
Hi I was thinking about using this for just a receiving antenna in which case I have a manual antenna tuner the mfj959c this would just be the receiving antenna would anyone recommend this over an end-fed. At present I'm using a qso king 117 ft 160 to 6 m antenna and it's pretty good but I really want to be hearing the 80 40 and 160 bands as full as possible for my icom r75 and alinco dxr8t
 

prcguy

Member
Joined
Jun 30, 2006
Messages
10,576
Location
So Cal - Richardson, TX - Tewksbury, MA
The Sigma HF-X80 is basically a dummy load on a stick and about the same as a Comet CHA-250B. They are really grim on 40m and below and not that good 20m and up. These antennas have a 5:1 balun with 20 something feet of aluminum tubing attached. Did I mention grim? And they are really expensive for what you get.

Regarding the QSO King, its a 9:1 balun sold with various lengths of wire and 73ft is common length. Side by side comparisons of a QSO King to a 64ft 40 through 10m End Fed Half Wave shows the KSO is not King and I know people who flat out could not make contacts with a QSO King antenna and swapping it out with an End Fed Half Wave in the exact same location made contacts. The downside to an EFHW is its going to be 133ft long for an 80 through 10m version, which works really well, or about 265ft long for a 160m and up version.

Another potential problem is antenna height on 160m. I played with full size and a trap loaded 160m dipole out in the So Cal desert with the apex at about 35ft and couldn't talk to anybody even though the antenna tuned up ok. The band actually seemed quite dead with these low dipoles and they need to be much higher, otherwise the efficiency in literally in the dirt. On the same evening as the low dipole disappointment on 160, I assembled and fired up a 32ft vertical with lots of radials on the ground and a good antenna tuner at the base and the 160m band came alive with the vertical and I made lots of contacts on the vertical where the low dipole was just dead.

If you don't have room for a very long but resonant EFHW on 80 and 160 or the height to make it play well, an active loop might be the next best thing for receive only. Something like the W6LVP loop works fantastic on 160 through 10m and it can do this sitting on your roof or a tripod close to the ground or whatever. It also has the ability to null out interference by rotating it but the null is very sharp and I can just park mine in one spot and its good for about 98% of the things I would use it for.

Hi I was thinking about using this for just a receiving antenna in which case I have a manual antenna tuner the mfj959c this would just be the receiving antenna would anyone recommend this over an end-fed. At present I'm using a qso king 117 ft 160 to 6 m antenna and it's pretty good but I really want to be hearing the 80 40 and 160 bands as full as possible for my icom r75 and alinco dxr8t
 

stormtracker78

Member
Premium Subscriber
Joined
Feb 6, 2011
Messages
114
Location
Cameron County, Tx
Ty so much! I do have room for the 133ft EFHW sadly not enough for the 256 ft for the 160 meter my spiderbeams came in this week replacing my
existing homemade electrical conduit antenna which is 25 feet high I wanted to get it to at least 30 or 35feet so I was thinking before I replace the antenna with the spiderbeams I might look at a vertical or see what options I have for a true resonant EFHW if any are better than the antenna I already have. could I somehow turn the spiderbeam into a vertical antenna and pick up 160 meters all transmissions and broadcasts as well as you did with yours?
 

prcguy

Member
Joined
Jun 30, 2006
Messages
10,576
Location
So Cal - Richardson, TX - Tewksbury, MA
The Spiderbeam is made for 20m and higher in frequency, I don't think it will pick up much on 160 or even 80m, its just too small. However a moderate size vertical that is tuned to resonance or matched to your feedline can do ok on 160m as my 32ft whip did. I had another similar experience at a remote controlled site where I have a ZS6BKW 94ft dipole at about 25ft off the ground and horizontal and a DX Engineering 43ft vertical on the same property.

The DX Engineering vertical originally came with a 4:1 balun, which didn't work on any band very well but it did receive some guys out to about 200mi on 160m where the ZS6BKW dipole was silent on 160m, not a peep. I later replaced the 4:1 balun on the vertical with a remote antenna tuner right at the base of the antenna and it just came alive on all bands including 160m. Some times of the year I monitor 160 with this setup and push the tune button and it seems there is a conversation about every 10KHz on 160, the band is busy end to end using the vertical. Switching to the ZS6BKW it goes nearly silent and occasionally I can pick up maybe a few local strong stations but nothing compared to the tuned vertical.

A wire antenna like an EFHW or OCFD or resonant dipole on 80m can do ok at 25-30ft off the ground but there is something about 160m that just doesn't work at those heights. So I don't think you will be very happy with any horizontal wire antenna for 160 unless you get it up really high or configure it as an inverted L with the vertical going up at least 30-40ft and then going horizontal for a ways and with a tuner at the base over some ground plane. This seems to be a common antenna being used on 160 and many of the people I hear on my remote station are using an inverted L.

Another thing to consider is verticals are usually a bit noisier one receive compared to a horizontal antenna, so even with a good performing vertical you will have some extra noise to deal with. So that brings me back to the active loop antenna, they are very quiet and if you have a noise problem its usually coming from a specific direction and you can null it out. I really think for receive only purposes and especially the lower bands your interested in would benefit from an active loop. If you were interested in transmitting then it would go a different direction.

Ty so much! I do have room for the 133ft EFHW sadly not enough for the 256 ft for the 160 meter my spiderbeams came in this week replacing my
existing homemade electrical conduit antenna which is 25 feet high I wanted to get it to at least 30 or 35feet so I was thinking before I replace the antenna with the spiderbeams I might look at a vertical or see what options I have for a true resonant EFHW if any are better than the antenna I already have. could I somehow turn the spiderbeam into a vertical antenna and pick up 160 meters all transmissions and broadcasts as well as you did with yours?
 

stormtracker78

Member
Premium Subscriber
Joined
Feb 6, 2011
Messages
114
Location
Cameron County, Tx
Im greatly thankful for the advice! Ok loop it is any recommendations on height and also direction for 160 meter?does it also receive broadside like the wire antennas?
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,490
Location
Bowie, Md.
No, many loops receive best along the plane of the loop element. So if the loop element points n/s, that's the direction it will favor. Loops are usually mounted no more than a couple of meters off the ground, and you can use a light duty TV rotator as the wind load is very small.

Interestingly some folks have been experimenting with mounting the loop horizontally instead of the normal vertical, and mount it higher, it becomes nearly omnidirectional.

However directivity becomes much less of an issue as you get higher in frequency - around 3 Mhz or so, skywave propagation becomes more dominant. At 160, you are beginning to get close to this range. On 80 and 40, you might not notice much, if any.

We have another forum for receiving antennas but to get you started, here's our wiki on the subject....


Mike
 
Top